Friday, June 10, 2011

Number 18

This past call, I dealt with the 2nd sickest pheo patients in my career (yet). This would have been my 18th pheochromocytoma patient.Mr. K presented to the ER with pleuritic chest pains. During the workup which included a CT chest to rule out a pulmonary embolism; that caught a glimpse of his adrenals which contained a 6.6 cm heterogenous mass. Aside from the chest pains, he was pretty asymptomatic, with reportedly a history of benign essentially hypertension well controlled with an ACE-inhibitor.When I saw him in the hospital, I reviewed the function of the gland, but also assured him that most masses are nonfunctioning though the sheer size of the tumor probably will necessitate adrenalectomy eventually. He looked great, and was normotensive. We also started biochemical testing then, though I'm often hesitant to initiate testing in inpatients as the probability of a false positive increases.I was called that night by the nurses because they had trouble with his blood pressure. 'Trouble' was probably the understatement of the year. So fluctuant was his BP, that they transferred him to telemetry. One minute his BP was 90/50, while the next it was clear up into 240/120s. Even on the arterial line. My pretest probability for a pheochromocytoma went from 'low' to 'almost definite'.In the outpatient setting, treatment of pheochromocytoma begins with adequate hydration as although patients may be hypertensive (caveat: most patients are NOT hypertensive) they tend to be intravascularly dry. I also tell them to tank up on salt (one of the 2, well maybe 3 conditions in which an endo might tell you to take MORE salt. Can you guess the other 2?). Alpha blockade is started first (classic medschool exam question) and while there are numerous you can pick from, I start with the shorter acting Phenoxybenzamine. The shorter duration of action allows for better titration of doses. My personal goal is to see a systolic drop of 15 to 20 mm Hg on standing with no reflex tachycardia though you may also pick an absolute BP goal. Once the patient is adequately blocked, a beta blocker is then started. For select patients, we add a 3rd line agent a few days before surgery: Metyrosine, to deplete adrenal catecholamine levels, that is if you can get your hands on it.For Mr. K, by the time I got to the hospital, his primary team had decided to intubate him for respiratory distress; his blood pressure remained mostly high though these were peppered with marked drops. In these situations, regular alpha blockade would not be fast-acting enough. Throughout the night, we resorted to Nitroglycerin and then Nipride, Nicardipine and finally Phentolamine. For the next 24 hours he remained fluctuant, at times with his BP so high that many of us feared he would stroke out, while at other times his BP was so low that they had trouble feeling a pulse. It was touch and go for the 5 days he was in the ICU though things eventually stabilized enough that he was extubated and we transitioned him to the usual Phenoxybenzamine and then a beta blocker.And so, when I saw him in clinic 2 days ago for follow up, I could not help myself but to give him a big handshake and a hug- he was out of it for most of the time in the ICU, but his family was there and they knew how worried we were. It was with a great sense of relief to see Mr. K walking and talking normally, cognitively intact.He's not out of the woods yet obviously. But I'm pleased by his progress and the level of his alpha and beta blockade. He's probably pretty well-prepped for surgery which will happen in a week. And God willing, things should turn out well.Post-op, it's necessary to reassess things biochemically as there is a chance of metastatic pheochromocytoma- patients should undergo repeat 24-hour urine catecholamine and metanephrine testing. If biochemistry remain abnormal, then imaging for metastatic disease is necessary, whether you use MIBG or Octreotide or some other scan.

Some experts suggest that the biochemistry be done annually for life. At the recent meeting I attended, some actually advocate genetic testing in ALL pheo patients (not just paraganglioma) as the incidence of familial pheo appears to be much higher than what the 10% rule suggests.

Will keep my fingers crossed that Mr. K sails through surgery, which he should. We had him see a very skilled surgeon and he's young enough that I don't anticipate any problems.

And so, that was my 2nd scariest pheo patient. One of these days, I'll tell you about my SICKEST patient.

The main other situation I tell patients to tank up on salt is in the workup of primary aldosteronism; after the screening aldo:renin, the confirmatory test involves oral salt loading and a 24-hr urine aldosterone and Na measurement.I'll accept the Addison's answer though technically in those patients the ideal treatment isn't so much salt loading, but to replace the mineraolocorticoid.

About Me

A Malaysian endocrinologist, trained in a major academic center in USA, and now starting out in the world of practice after 12 years of training.
To maintain patient confidentiality, names, ages and genders have been altered (And some stories totally fabricated to fool gullible readers).
This site is not meant to provide medical advice or consultation.